1. Field of the Invention
The invention relates to a process for the preparation of 2,6,10,15,19,23-hexamethyl tetracosane and isomers thereof having a hexamethyl tetracosane structure from certain vegetable fats and oils.
2. Description of the Prior Art
Hexamethyl tetracosanes are derivatives of 2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22-tetracosahexene, a naturally occurring isoprenoid hydrocarbon, of the terpene series. It is, to be precise, a triterpene.
A technical grade thereof, from animal source, was isolated in 1906 from the unsaponifiable matter of shark liver oil. The hydrogenated 2,6,10,15,19,23-hexamethyl tetracosane was obtained in 1923 and the structure was defined in 1929.
The technical grade of animal source hexamethyl tetracosahexene, obtained from shark liver oil, has a strong fish odour and is chemically unstable due to its high degree of unsaturation (iodine number 370), is easily oxidised (becomes stale) and has a tendency to polymerise or "dry out", providing viscous products or even skins.
Due to the above, it was hitherto not possible to use hexamethyl tetracosahexene of animal source, independently of the minor components and impurities from said origin, directly in cosmetics or other applications (lubricants, dielectric fluids, heat transmission fluids, etc.), it having been necessary to hydrogenise it completely prior to use. The hexamethyl tetracosane thus obtained is very stable chemically, has no odour and is fully compatible with the skin. Use of the technical grade of animal hexamethyl tetracosane started in 1950 and has continued down to the present time, the use having grown considerably.
All the naturally occurring hexamethyl tetracosane is currently being obtained from shark liver oil which, owing to the insufficient number of catches and notwithstanding the animal origin of the technical grade and the impurities or minor components involved therewith, causes powerful tensions in the market, caused by the imbalance between a short-falling, irregular supply, against a constantly increasing demand.